Head Of U.S. Nuclear Watchdog Emphasizes Preparing For Unknown

Speaking two years after the Fukushima Daiichi nuclear power plant disaster in Japan, Allison M. Macfarlane, a geologist who became chairwoman of the five-member commission last July, cited aging nuclear reactors, terrorist attacks and natural disasters, saying, “we don’t know everything about how the Earth behaves, and we must factor this into how we approach nuclear safety.’’